In some known conventional information communication apparatuses, communication systems and communication methods, a user of the information communication apparatus in the communication system is supplied with information which identifies the user (hereinafter, referred to as communication addressee information). In the event that the user owns a plurality of information communication apparatuses and changes the information communication apparatus he is currently using to another one during ongoing communication, he can continue the communication as an identified user (hereinafter, referred to as communication shift) (for example, see the Patent Document 1). Examples of the communication addressee information are telephone number and IP address.    Patent Document: Japanese Patent Applications Laid-Open No. 2005-260348 (for example, see Page 1, FIG. 1)